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  • 1
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Ecology Letters 12 (2009): E15-E18, doi:10.1111/j.1461-0248.2009.01332.x.
    Beschreibung: Hartley et al. question whether reduction in Rmass, under experimental warming, arises because of the biomass method. We show the method they treat as independent yields the same result. We describe why the substrate-depletion hypothesis cannot alone explain observed responses, and urge caution in the interpretation of the seasonal data.
    Beschreibung: This research was supported by the Office of Science (BER), U.S. Department of Energy, the Andrew W. Mellon Foundation and U.S. National Science Foundation grants to the Coweeta LTER program.
    Schlagwort(e): Acclimation ; Adaptation ; Soil respiration ; Thermal biology ; Temperature ; Carbon cycling ; Climate change ; Climate warming ; Microbial community ; CO2
    Repository-Name: Woods Hole Open Access Server
    Materialart: Preprint
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Tree Physiology 31 (2011): 707-717, doi:10.1093/treephys/tpr066.
    Beschreibung: Examining the responses of root standing crop (biomass and necromass) and chemistry to soil warming is crucial for understanding root dynamics and functioning in the face of global climate change. We assessed the standing crop, total nitrogen (N) and carbon (C) compounds in tree roots and soil net N mineralization over the growing season after six years of experimental soil warming in a temperate deciduous forest in 2008. Roots were sorted into four different categories: live and dead fine roots (≤ 1 mm in diameter) and live and dead coarse roots (1-4 mm in diameter). Total root standing crop (live plus dead) in the top 10 cm of soil in the warmed area was 42.5% (378.4 vs. 658.5 g m-2) lower than in the control area, while the live root standing crops in the warmed area was 62% lower than in the control area. Soil net N mineralization over the growing season increased by 79.4% in the warmed relative to the control area. Soil warming did not significantly change the concentrations of C and carbon compounds (sugar, starch, hemicellulose, cellulose, and lignin) in the four root categories. However, total N concentration in the live fine roots in the warmed area was 10.5% (13.7 vs. 12.4 mg g-1) higher and C:N ratio was 8.6% (38.5 vs. 42.1) lower than in the control area. The increase in N concentration in the live fine roots could be attributed to the increase in soil N availability due to soil warming. Net N mineralization was negatively correlated to both live and dead fine roots in the mineral soil that is home to the majority of roots, suggesting that soil warming increases N mineralization, decreases fine root biomass, and thus decreases carbon allocation belowground.
    Beschreibung: This study was funded by the US National Science Foundation (NSF-AGS-1005663) and the Marine Biological Laboratory (to JT), China Scholarship Council (to YZ), Harvard Forest Long Term Ecological Research (NSF-DEB-0620443) and the National Institute for Climate Change Research (DOE-DE-FCO2-06-ER64157) (to JM).
    Beschreibung: 2012-08-02
    Schlagwort(e): Carbon ; Nitrogen ; Root biomass ; Root diameter ; Root necromass
    Repository-Name: Woods Hole Open Access Server
    Materialart: Preprint
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © Ecological Society of America, 2007. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 17 (2007): 1198–1212, doi:10.1890/05-1690.
    Beschreibung: The composition and successional status of a forest affect carbon storage and net ecosystem productivity, yet it remains unclear whether elevated atmospheric carbon dioxide (CO2) will impact rates and trajectories of forest succession. We examined how CO2 enrichment (+200 μL CO2/L air differential) affects forest succession through growth and survivorship of tree seedlings, as part of the Duke Forest free-air CO2 enrichment (FACE) experiment in North Carolina, USA. We planted 2352 seedlings of 14 species in the low light forest understory and determined effects of elevated CO2 on individual plant growth, survival, and total sample biomass accumulation, an integrator of plant growth and survivorship over time, for six years. We used a hierarchical Bayes framework to accommodate the uncertainty associated with the availability of light and the variability in growth among individual plants. We found that most species did not exhibit strong responses to CO2. Ulmus alata (+21%), Quercus alba (+9.5%), and nitrogen-fixing Robinia pseudoacacia (+230%) exhibited greater mean annual relative growth rates under elevated CO2 than under ambient conditions. The effects of CO2 were small relative to variability within populations; however, some species grew better under low light conditions when exposed to elevated CO2 than they did under ambient conditions. These species include shade-intolerant Liriodendron tulipifera and Liquidambar styraciflua, intermediate-tolerant Quercus velutina, and shade-tolerant Acer barbatum, A. rubrum, Prunus serotina,Ulmus alata, and Cercis canadensis. Contrary to our expectation, shade-intolerant trees did not survive better with CO2 enrichment, and population-scale responses to CO2 were influenced by survival probabilities in low light. CO2 enrichment did not increase rates of sample biomass accumulation for most species, but it did stimulate biomass growth of shade-tolerant taxa, particularly Acer barbatum and Ulmus alata. Our data suggest a small CO2 fertilization effect on tree productivity, and the possibility of reduced carbon accumulation rates relative to today's forests due to changes in species composition.
    Beschreibung: This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-95ER62083, and by Terrestrial Ecosystems and Global Change (TECO) Grant No. DE-F602-97ER62463.
    Schlagwort(e): Bayesian analysis ; Carbon dioxide (CO2) enrichment ; Forest succession ; Global change ; Hierarchical Bayes
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Ecology Letters 11 (2008): 1316-1327, doi:10.1111/j.1461-0248.2008.01251.x.
    Beschreibung: In the short-term heterotrophic soil respiration is strongly and positively related to temperature. In the long-term its response to temperature is uncertain. One reason for this is because in field experiments increases in respiration due to warming are relatively short-lived. The explanations proposed for this ephemeral response include depletion of fast-cycling, soil carbon pools and thermal adaptation of microbial respiration. Using a 〉15 year soil warming experiment in a mid-latitude forest, we show that the apparent ‘acclimation’ of soil respiration at the ecosystem scale results from combined effects of reductions in soil carbon pools and microbial biomass, and thermal adaptation of microbial respiration. Mass specific respiration rates were lower when seasonal temperatures were higher, suggesting that rate reductions under experimental warming likely occurred through temperature-induced changes in the microbial community. Our results imply that stimulatory effects of global temperature rise on soil respiration rates may be lower than currently predicted.
    Beschreibung: This research was supported by the Office of Science (BER), U.S. Department of Energy and the Andrew W. Mellon Foundation.
    Schlagwort(e): Acclimation ; Adaptation ; Soil respiration ; Thermal biology ; Temperature ; Carbon cycling ; Climate change ; Climate warming ; Microbial community ; CO2
    Repository-Name: Woods Hole Open Access Server
    Materialart: Preprint
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © NRC Research Press, 2009. This article is posted here by permission of NRC Research Press for personal use, not for redistribution. The definitive version was published in Canadian Journal of Forest Research 39 (2009): 213-230, doi:10.1139/X08-185.
    Beschreibung: Increasing temperatures, precipitation extremes, and other anthropogenic influences (pollutant deposition, increasing carbon dioxide) will influence future forest composition and productivity in the northeastern United States and eastern Canada. This synthesis of empirical and modeling studies includes tree DNA evidence suggesting tree migrations since the last glaciation were much slower, at least under postglacial conditions, than is needed to keep up with current and future climate warming. Exceedances of US and Canadian ozone air quality standards are apparent and offset CO2-induced gains in biomass and predispose trees to other stresses. The deposition of nitrogen and sulfate in the northeastern United States changes forest nutrient availability and retention, reduces reproductive success and frost hardiness, causes physical damage to leaf surfaces, and alters performance of forest pests and diseases. These interacting stresses may increase future tree declines and ecosystem disturbances during transition to a warmer climate. Recent modeling work predicts warmer climates will increase suitable habitat (not necessarily actual distribution) for most tree species in the northeastern United States. Species whose habitat is declining in the northeastern United States currently occur in Canadian forests and may expand northward with warming. Paleoecological studies suggest local factors may interact with, even overwhelm, climatic effects, causing lags and thresholds leading to sudden large shifts in vegetation.
    Beschreibung: Funding for this study was provided by the Northeastern States Research Cooperative. J.E. Mohan and data from Harvard Forest were supported by Long-term Ecological Research funding through the National Science Foundation (DEB-0620443 to J. Melillo), and by National Institute for Climate Change Research funding through the Department of Energy (DE-FC02-06ER64157).
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © Ecological Society of America, 2008. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecology 89 (2008): 585–587, doi:10.1890/07-0660.1.
    Beschreibung: This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant Number DE-FG02-95ER62083 and Terrestrial Ecosystems and Global Change (TECO) Grant Number DE-F602-97ER62463.
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2022-05-25
    Beschreibung: © The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Oecologia 168 (2012): 819-828, doi:10.1007/s00442-011-2133-7.
    Beschreibung: Global climate change is expected to affect terrestrial ecosystems in a variety of ways. Some of the more well-studied effects include the biogeochemical feedbacks to the climate system that can either increase or decrease the atmospheric load of greenhouse gases such as carbon dioxide and nitrous oxide. Less well-studied are the effects of climate change on the linkages between soil and plant processes. Here, we report the effects of soil warming on these linkages observed in a large field manipulation of a deciduous forest in southern New England, USA, where soil was continuously warmed 5°C above ambient for 7 years. Over this period, we have observed significant changes to the nitrogen cycle that have the potential to affect tree species composition in the long term. Since the start of the experiment, we have documented a 45% average annual increase in net nitrogen mineralization and a three-fold increase in nitrification such that in years 5 through 7, 25% of the nitrogen mineralized is then nitrified. The warming-induced increase of available nitrogen resulted in increases in the foliar nitrogen content and the relative growth rate of trees in the warmed area. Acer rubrum (red maple) trees have responded the most after 7 years of warming, with the greatest increases in both foliar nitrogen content and relative growth rates. Our study suggests that considering species-specific responses to increases in nitrogen availability and changes in nitrogen form is important in predicting future forest composition and feedbacks to the climate system.
    Beschreibung: This work was supported by the National Institute for Climate Change Research (DOE-DE-FCO2-06-ER64157), DOE BER (DE-SC0005421) and the Harvard Forest Long-Term Ecological Research program (NSF-DEB-0620443).
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/msword
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 1365-2486
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie , Energietechnik , Geographie
    Notizen: Genetic variation in plant response to atmospheric carbon dioxide (CO2) may have influenced paleo-vegetation dynamics and could determine how future elevated CO2 drives plant evolution and ecosystem productivity. We established how levels of relatedness – the maternal family, population, and provenance – affect variation in the CO2 response of a species. This 2-year growth chamber experiment focused on the germination, growth, biomass allocation, and survivorship responses of Acer rubrum to four concentrations of CO2: 180, 270, 360, and 600 μL L−1– representing Pleistocene through potential future conditions. We found that all levels of relatedness interacted with CO2 to contribute to variation in response. Germination responses to CO2 varied among families and populations, growth responses depended on families and regions of origin, and survivorship responses to CO2 were particularly affected by regional identities. Differences among geographic regions accounted for 23% of the variation in biomass response to CO2. If seeds produced under subambient CO2 conditions behave similarly, our results suggest that A. rubrum may have experienced strong selection on seedling survivorship at Pleistocene CO2 levels. Further, this species may evolve in response to globally rising CO2 so as to increase productivity above that experimentally observed today. Species responses to future atmospheric CO2 and the accompanying biotic effects on the global carbon cycle will vary among families, populations, and provenances.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2009-02-01
    Beschreibung: Increasing temperatures, precipitation extremes, and other anthropogenic influences (pollutant deposition, increasing carbon dioxide) will influence future forest composition and productivity in the northeastern United States and eastern Canada. This synthesis of empirical and modeling studies includes tree DNA evidence suggesting tree migrations since the last glaciation were much slower, at least under postglacial conditions, than is needed to keep up with current and future climate warming. Exceedances of US and Canadian ozone air quality standards are apparent and offset CO2-induced gains in biomass and predispose trees to other stresses. The deposition of nitrogen and sulfate in the northeastern United States changes forest nutrient availability and retention, reduces reproductive success and frost hardiness, causes physical damage to leaf surfaces, and alters performance of forest pests and diseases. These interacting stresses may increase future tree declines and ecosystem disturbances during transition to a warmer climate. Recent modeling work predicts warmer climates will increase suitable habitat (not necessarily actual distribution) for most tree species in the northeastern United States. Species whose habitat is declining in the northeastern United States currently occur in Canadian forests and may expand northward with warming. Paleoecological studies suggest local factors may interact with, even overwhelm, climatic effects, causing lags and thresholds leading to sudden large shifts in vegetation.
    Print ISSN: 0045-5067
    Digitale ISSN: 1208-6037
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2014-01-01
    Print ISSN: 0361-5995
    Digitale ISSN: 1435-0661
    Thema: Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Publiziert von Wiley
    Standort Signatur Erwartet Verfügbarkeit
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